For the puff pastry pirogi, sauté the onion in the butter, add the mushrooms, sauté briefly, season with salt, pepper and parsley. Remove from heat and add a little yolk.
Divide the dough into 10 squares. Place the mushroom mixture on top, brush the edges with water and fold over one corner to form a triangle.
Press the sides tight, place the squares on a cold rinsed baking tray, prick several times and brush with the remaining yolk.
Leave to stand for 15 minutes, then bake in a preheated oven at 220 °C for about 20 minutes.
Preparation Tip:
With the puff pastry pierogi fit all leaf salads.